The subject matter disclosed herein relates to knock sensors, and more specifically, to knock sensors mounted to large, multi-cylinder combustion engines for component condition detection.
Combustion engines typically combust a carbonaceous fuel, such as natural gas, gasoline, diesel, and the like, and use the corresponding expansion of high temperature and pressure gases to apply a force to certain components of the engine, e.g., piston disposed in a cylinder, to move the components over a distance. Each cylinder may include one or more valves that open and close correlative with combustion of the carbonaceous fuel. For example, an intake valve may direct an oxidizer such as air into the cylinder, which is then mixed with fuel and combusted. Combustion fluids, e.g., hot gases, may then be directed to exit the cylinder via an exhaust valve. Accordingly, the carbonaceous fuel is transformed into mechanical motion, useful in driving a load. For example, the load may be a generator that produces electric power.
Knock sensors can be used to monitor multi-cylinder combustion engines. A knock sensor can be mounted to the exterior of an engine cylinder and used to determine whether or not the engine is running as desired. Knock sensors are typically checked by measuring the impedance of the knock sensor, which may require the engine to be shut down. Measuring the impedance of the knock sensor indicates only whether the knock sensor is present, not whether the knock sensor is functioning properly or wired correctly. It would be desirable to improve the derivation of knock sensor conditions.